The 3rd Generation Partnership Project (3GPP) is currently developing protocols for the next generation wireless communication networks, also referred to as New Radio (NR). NR will enable new use cases for cellular access, and also increase the capacity for existing data applications. Even though the capacity of a system under NR may increase, there still can be situations where the base stations (e.g., next generation node Bs (gNBs)) and/or core networks (CNs) of the system may become overloaded. For example, a system overload may occur when a large number of user equipments (UEs) try to access the system in a synchronized manner (e.g., at the same time).
In a fourth generation (4G) wireless network, such as long term evolution (LTE), evolved LTE (eLTE), or LTE-Advanced (LTE-A), a radio access network (RAN) is responsible for activating access control when the RAN or the CN is overloaded. For example, a current access control scheme under a 4G wireless network may be performed in the RAN (e.g., RAN based), which primarily bars low priority UEs from attempting to perform random access procedures to transition from RRC_IDLE state to RRC_CONNECTED state. That is, the low priority UEs can be barred by the RAN from accessing the wireless network for a predetermined period of time when the RAN or CN is overloaded.
Based on the current 3GPP standard discussion, in addition to the current RRC_CONNECTED and RRC_IDLE states, a new RRC state, RRC_INACTIVE state, is introduced in the NR wireless networks. RRC_INACTIVE state under an NR wireless network is configured by a base station (e.g., gNB), and may be invisible to the CN. For example, when a base station (e.g., gNB) suspends a UE from RRC_CONNECTED to RRC_INACTIVE state, the CN may not receive a notification of such, and may still consider the UE as in RRC_CONNECTED state. While in RRC_INACTIVE state, the UE may transfer uplink (UL) data to the base state (e.g., gNB) without undergoing RRC state transition (e.g., without transitioning from RRC_INACTIVE state to RRC_CONNECTED state).
In the legacy 4G wireless networks, when the CN is overloaded and sends instructions to the RANs to block or bar traffic, the RANs may set up barring parameters to bar or block RRC_IDLE UEs from performing RRC state transition to RRC_CONNECTED state for data transmission. However, the access control schemes under the 4G wireless networks do not take into account of the newly introduced RRC_INACTIVE UEs that are capable of direct data uplink transmission to the base station without transitioning into RRC_CONNECTED state. As such, the legacy 4G wireless networks cannot effectively treat the RRC_INACTIVE UEs when the base station and/or the CN is overloaded.
For example, if RRC_INACTIVE UEs are present in a wireless network, and the CN does not know that some UEs under the RAN are suspended in the RRC_INACTIVE state (e.g., temporarily do not have data to upload), the CN may underestimate the network traffic condition in the RANs because of the presence of the RRC_INACTIVE UEs. That is, the CN may consider the RRC_INACTIVE UEs are in the RRC_CONNECTED state, and use their current data rates for the network traffic estimate. However, when these RRC_INACTIVE UEs start transferring data (e.g., using 2-step or 4-step RACH procedure) to their base stations, the actual data traffic would be greater than what the CN had originally estimated (e.g., the RAN continues to bring in additional traffic from the RRC_INACTIVE UEs to the CN), thereby exacerbating the traffic condition and overloading the base stations and/or the CN.
Thus, there is a need in the art for access control in new radio wireless networks to block traffic by dynamically assigning access control categorizations and sub-categorizations (e.g., barring factors) based on traffic conditions, to take into account of and manage each of the RRC states in NR, to conserve radio resources (e.g., stop unnecessary consumption of radio resource), and to preserve base station and/or CN's processing capacity for high priority traffic, data and/or applications from specific UEs.